Special Counsel Robert Mueller is digging deeper into Trump ally and Blackwater founder Erik Prince, according to multiple sources with knowledge of the matter.

Prince, America’s most famous private military contractor, acknowledged last week that he “cooperated” with Mueller’s investigation of Russian interference in the 2016 presidential election after falling under scrutiny amid questions about an alleged effort to establish a backchannel between the Trump administration and the Kremlin, something Prince has vehemently denied.

ABC News has since learned that Mueller is also reviewing Prince’s communications. In response to questions from ABC News, a spokesperson for Prince released a statement noting that Prince has provided Mueller with “total access to his phone and computer.”

“As Mr. Prince told the Daily Beast he has spoken voluntarily with Congress and also cooperated completely with the Special Counsel’s investigation, including by providing them total access to his phones and computer,” the spokesperson said. “Mr. Prince has a lot of opinions about the various investigations, but there is no question that they are important and serious, and so Mr. Prince will keep his opinions to himself for now and to let the investigators do their work. All we will add is that much of the reporting and speculation about Mr. Prince in the media is inaccurate, and we are confident that when the investigators have finished their work, we will be able to put these distractions to the side.”